.bigimg{
    width: 550px;
    height: 500px;
}
ul{
    width: 550px;
    display: flex;
    height: 105px;
    margin: auto;
    justify-content: space-evenly;
    border: 1px solid black;
}
ul li{
    list-style: none;
    width: 105px;
    cursor: pointer;
}
ul li img{
    width: 100%;
    height: 100px;
}
.bg{
    border: 2px solid red;
}